Harvest now, decrypt later (HNDL) attacks involve collecting encrypted data today to break it with quantum computers tomorrow. This silent, long-term threat poses a significant risk to individuals, organizations, and governments worldwide. As quantum computing advances, today's encryption could become obsolete, making stored data vulnerable to decryption by attackers who have already harvested it. Organizations must consider proactive defenses such as post-quantum cryptography (PQC), forward secrecy, re-encryption, and quantum key distribution (QKD) to protect themselves against HNDL attacks. The sooner they begin experimenting with and adopting PQC algorithms, the better prepared they'll be when the quantum era arrives. Waiting too long could mean that data being encrypted today may no longer be secure tomorrow, especially if it's already been silently harvested.